IL-10 modulates in vitro multinucleate giant cell formation in human tuberculosis

Formation and biological activities of foreign body giant cells in response to biomaterials

The integration of biomaterials in medical applications triggers the foreign body response (FBR), a multi-stage immune reaction characterized by the formation of foreign body giant cells (FBGCs). Originating from the fusion of monocyte/macrophage lineage cells, FBGCs are pivotal participants during tissue-material interactions. This review provides an in-depth examination of the molecular processes during FBGC formation, highlighting signaling pathways and fusion mediators in response to both exogenous and endogenous stimuli. Moreover, a wide range of material-specific characteristics, such as surface chemical and physical properties, has been proven to influence the fusion of macrophages into FBGCs. Multifaceted biological activities of FBGCs are also explored, with emphasis on their phagocytic capabilities and extracellular secretory functions, which profoundly affect the vascularization, degradation, and encapsulation of the biomaterials. This review further elucidates the heterogeneity of FBGCs and their diverse roles during FBR, as demonstrated by their distinct behaviors in response to different materials. By presenting a comprehensive understanding of FBGCs, this review intends to provide strategies and insights into optimizing biocompatibility and the therapeutic potential of biomaterials for enhanced stability and efficacy in clinical applications. STATEMENT OF SIGNIFICANCE: As a hallmark of the foreign body response (FBR), foreign body giant cells (FBGCs) significantly impact the success of implantable biomaterials, potentially leading to complications such as chronic inflammation, fibrosis, and device failure. Understanding the role of FBGCs and modulating their responses are vital for successful material applications. This review provides a comprehensive overview of the molecules and signaling pathways guiding macrophage fusion into FBGCs. By elucidating the physical and chemical properties of materials inducing distinct levels of FBGCs, potential strategies of materials in modulating FBGC formation are investigated. Additionally, the biological activities of FBGCs and their heterogeneity in responses to different material categories in vivo are highlighted in this review, offering crucial insights for improving the biocompatibility and efficacy of biomaterials.

Progress of the Art of Macrophage Polarization and Different Subtypes in Mycobacterial Infection

Mycobacteriosis, mostly resulting from Mycobacterium tuberculosis (MTb), nontuberculous mycobacteria (NTM), and Mycobacterium leprae (M. leprae), is the long-standing granulomatous disease that ravages several organs including skin, lung, and peripheral nerves, and it has a spectrum of clinical-pathologic features based on the interaction of bacilli and host immune response. Histiocytes in infectious granulomas mainly consist of infected and uninfected macrophages (Mφs), multinucleated giant cells (MGCs), epithelioid cells (ECs), and foam cells (FCs), which are commonly discovered in lesions in patients with mycobacteriosis. Granuloma Mφ polarization or reprogramming is the crucial appearance of the host immune response to pathogen aggression, which gets a command of endocellular microbe persistence. Herein, we recapitulate the current gaps and challenges during Mφ polarization and the different subpopulations of mycobacteriosis.

The Granule Size Mediates the In Vivo Foreign Body Response and the Integration Behavior of Bone Substitutes

The physicochemical properties of synthetically produced bone substitute materials (BSM) have a major impact on biocompatibility. This affects bony tissue integration, osteoconduction, as well as the degradation pattern and the correlated inflammatory tissue responses including macrophages and multinucleated giant cells (MNGCs). Thus, influencing factors such as size, special surface morphologies, porosity, and interconnectivity have been the subject of extensive research. In the present publication, the influence of the granule size of three identically manufactured bone substitute granules based on the technology of hydroxyapatite (HA)-forming calcium phosphate cements were investigated, which includes the inflammatory response in the surrounding tissue and especially the induction of MNGCs (as a parameter of the material degradation). For the in vivo study, granules of three different size ranges (small = 0.355-0.5 mm; medium = 0.5-1 mm; big = 1-2 mm) were implanted in the subcutaneous connective tissue of 45 male BALB/c mice. At 10, 30, and 60 days post implantationem, the materials were explanted and histologically processed. The defect areas were initially examined histopathologically. Furthermore, pro- and anti-inflammatory macrophages were quantified histomorphometrically after their immunohistochemical detection. The number of MNGCs was quantified as well using a histomorphometrical approach. The results showed a granule size-dependent integration behavior. The surrounding granulation tissue has passivated in the groups of the two bigger granules at 60 days post implantationem including a fibrotic encapsulation, while a granulation tissue was still present in the group of the small granules indicating an ongoing cell-based degradation process. The histomorphometrical analysis showed that the number of proinflammatory macrophages was significantly increased in the small granules at 60 days post implantationem. Similarly, a significant increase of MNGCs was detected in this group at 30 and 60 days post implantationem. Based on these data, it can be concluded that the integration and/or degradation behavior of synthetic bone substitutes can be influenced by granule size.

Review of the Effectiveness of Various Adjuvant Therapies in Treating Mycobacterium tuberculosis

Tuberculosis disease is caused by the bacterium Mycobacterium tuberculosis. It is estimated that 10 million people have developed tuberculosis disease globally, leading to 1.4 million deaths in 2019. Treatment of tuberculosis has been especially challenging due to the rise of multidrug-resistant (MDR-TB) and extensive drug-resistant (XDR-TB) tuberculosis. In addition to drug-resistant genotypes, the standard treatment of tuberculosis by first-line agents is also challenging due to toxicity and costs. In the last four decades, there have only been two new anti-tuberculosis agents—bedaquiline and delamanid. Therefore, shorter, safer, and more cost-effective therapies are needed to adequately treat tuberculosis. In this review, we explore various adjuvants such as glutathione, everolimus, vitamin D, steroid, aspirin, statin, and metformin and their usefulness in reducing the burden of tuberculosis. Glutathione, everolimus, aspirin, and metformin showed the most promise in alleviating the burden of tuberculosis. Despite their potential, more clinical trials are needed to unequivocally establish the effectiveness of these adjuvants as future clinical therapies. Methods: The journals for this review were selected by conducting a search via PubMed, Google Scholar, and The Lancet. Our first search included keywords such as “tuberculosis” and “adjuvant therapy.” From the search, we made a list of adjuvants associated with tuberculosis, and this helped guide us with our second online database search. Using the same three online databases, we searched “tuberculosis” and “respective therapy.” The adjuvants included in the paper were selected based on the availability of sufficient research and support between the therapy and tuberculosis. Adjuvants with minimal research support were excluded. There were no specific search criteria regarding the timing of publication, with our citations ranging between 1979 to 2021.

Apoptosis levels in bovine Johne's disease ileal lesions and association with bacterial numbers

Johne’s disease (JD) is a chronic granulomatous enteritis caused by Mycobacterium avium subsp. paratuberculosis (MAP). While it is generally accepted that MAP employs immune subversion mechanisms, aspects of the host-pathogen relationship are not fully understood. We sampled 3 ileal tissue sections from 17 naturally infected cattle (n = 51 sections) to analyze differences in cell types, apoptosis, and phagocytic cells. Diffuse multibacillary (DM) was the most common lesion type (n = 17) followed by diffuse intermediate (DI; n = 15). DM lesions had significantly greater proportion of Treg cells (CD3⁺ FoxP3⁺⁾ relative to all CD3⁺ T cells as compared to DI forms (P < .05). CD68⁺ individual cell size was significantly smaller in DM than in diffuse lymphocytic (DL) forms (P < .05). Area of caspase-3 positivity (apoptosis) was greater in DM lesions than DL (P < .05) and DI (P < .0001), and was linked to higher numbers of MAP within the macrophage.

Macrophage-specific responses to human- and animal-adapted tubercle bacilli reveal pathogen and host factors driving multinucleated cell formation

The Mycobacterium tuberculosis complex (MTBC) is a group of related pathogens that cause tuberculosis (TB) in mammals. MTBC species are distinguished by their ability to sustain in distinct host populations. While Mycobacterium bovis (Mbv) sustains transmission cycles in cattle and wild animals and causes zoonotic TB, M. tuberculosis (Mtb) affects human populations and seldom causes disease in cattle. The host and pathogen determinants underlying host tropism between MTBC species are still unknown. Macrophages are the main host cell that encounters mycobacteria upon initial infection, and we hypothesised that early interactions between the macrophage and mycobacteria influence species-specific disease outcome. To identify factors that contribute to host tropism, we analysed blood-derived primary human and bovine macrophages (hMϕ or bMϕ, respectively) infected with Mbv and Mtb. We show that Mbv and Mtb reside in different cellular compartments and differentially replicate in hMϕ whereas both Mbv and Mtb efficiently replicate in bMϕ. Specifically, we show that out of the four infection combinations, only the infection of bMϕ with Mbv promoted the formation of multinucleated giant cells (MNGCs), a hallmark of tuberculous granulomas. Mechanistically, we demonstrate that both MPB70 from Mbv and extracellular vesicles released by Mbv-infected bMϕ promote macrophage multinucleation. Importantly, we extended our in vitro studies to show that granulomas from Mbv-infected but not Mtb-infected cattle contained higher numbers of MNGCs. Our findings implicate MNGC formation in the contrasting pathology between Mtb and Mbv for the bovine host and identify MPB70 from Mbv and extracellular vesicles from bMϕ as mediators of this process.

The identification of host and pathogen factors contributing to host-pathogen interaction is crucial to understand the pathogenesis and dissemination of tuberculosis. This is particularly the case in deciphering the mechanistic basis for host-tropism across the MTBC. Here, we show that in vitro, M. bovis but not M. tuberculosis induces multinucleated cell formation in bovine macrophages. We identified host and pathogen mechanistic drivers of multinucleated cell formation: MPB70 as the M. bovis factor and bovine macrophage extracellular vesicles. Using a cattle experimental infection model, we confirmed differential multinucleated cell formation in vivo. Thus, we have identified host and pathogen factors that contribute to host tropism in human/bovine tuberculosis. Additionally, this work provides an explanation for the long-standing association of multinucleated cells with tuberculosis pathogenesis.

Characterization of macrophages, giant cells and granulomas during muscle regeneration after irradiation

Macrophages play a fundamental role in the different stages of muscle regeneration although the precise mechanisms involved are not entirely understood. Here we investigated the types of macrophages and cytokines that appeared in muscles after local gamma irradiation of mini-pigs that underwent no subsequent treatment or received three successive adipose tissue-derived stem cell (ASC) injections. Although some variability was observed among the three animals included in each study group, a general picture emerged. No macrophages appeared in control muscles from regions that had not been irradiated nor in muscles from irradiated regions derived from two animals. A third irradiated, but untreated animal, with characteristic muscle fibrosis and necrosis due to irradiation, showed invasion of M2 macrophages within small muscle lesions. In contrast, among the three ASC-treated and irradiated animals, one of them had completely recovered normal muscle architecture at the time of sampling with no invading macrophages, muscle from a second one contained mostly M1 macrophages and some M2-like macrophages whereas muscle from a third one displayed granulomas and giant cells. ASC treatment was associated with the presence of similar levels of pro-inflammatory cytokines within the two animals in the process of muscle regeneration whereas the levels of IL-4 and IL-10 expression were distinct from one animal to another. Microspectrofluorimetry and in situ hybridization revealed strong expression of TGF-β1 and TNFα in regenerating muscle. Overall, the data confirm the critical role of macrophages in muscle regeneration and suggest the involvement of a complex network of cytokine expression for successful recovery.

Early secreted antigenic target of 6-kDa of Mycobacterium tuberculosis induces transition of macrophages into epithelioid macrophages by downregulating iNOS / NO-mediated H3K27 trimethylation in macrophages

BACKGROUND

Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium tuberculosis (Mtb). Granuloma is a pathological feature of tuberculosis and is a tight immune cell aggregation caused by Mtb. The main constituent cells are macrophages and their derivative cells including epithelioid macrophages. However, the molecular mechanism of the transition has not been reported. The purpose of this study was to investigate whether early secreted antigenic target of 6-kDa (ESAT6) can induce the transition of bone marrow-derived macrophages (BMDMs) into epithelioid macrophages and its possible molecular mechanism.

METHODS

The recombinant ESAT6 protein was obtained from E.coli carrying esat6 gene after isopropyl β-d-thiogalactopyranoside (IPTG) induction. BMDMs were isolated from bone marrow of mice hind legs. Cells viability was detected by Cell Counting Kit 8 (CCK8) assays. The expression levels of mRNA and proteins were detected by qPCR and Western blot, or evaluated by flow cytometry. The expression level of nitric oxide (NO) was measured with a nitric oxide indicator.

RESULTS

ESAT6 could significantly induce mRNA and protein expression levels of a group of epithelioid macrophages marker molecules (EMMMs), including E-cadherin, junction plakoglobin, ZO1, desmoplakin, desmoglein3 and catenin porteins, in BMDMs. These events could be abrogated in macrophage from TLR2 deficiency mice. ESAT6 could also markedly induce iNOS/NO production that could significantly inhibit trimethylation of H3K27 in the cells. ESAT6-induced expressions of epithelioid macrophages marker molecules were significantly inhibited in the presence of H3K27 histone demethylase inhibitor GSK J1. Furthermore, ROS scavenging agent N,N'-Dimethylthiourea (DMTU) could markedly inhibit the transition induced by ESAT6 in macrophages.

CONCLUSION

This study demonstrates that ESAT6 bound with TLR2 can activate iNOS/NO and ROS signalings to reduce the trimethylation of H3K27 resulting in the increment of EMMMs expression that is beneficial to the transition of macrophages into epithelioid macrophages. However, hypoxia can inhibit this transition event. This study has provided new evidence of pathogenesis of granuloma caused by Mtb and also proposed new ideas for the treatment of TB.

Tumor Necrosis Factor-Alpha Antagonist Interferes With the Formation of Granulomatous Multinucleated Giant Cells: New Insights Into Mycobacterium tuberculosis Infection

More than half of tuberculosis cases in the world are due to resuscitation of dormant Mycobacterium tuberculosis (Mtb) sequestered into cell-derived structures called granulomas. It is fairly admitted that cytokines and more particularly Tumor Necrosis Factor (TNF)-α is critical in the control of Mtb infections and that anti-TNF-α drugs constitute one of the main risk factors for reactivation of latent Mtb infection. The aim of this study was to evaluate the role of etanercept, a dimeric fusion protein consisting of the extracellular ligand-binding portion of the human p75 TNF receptor linked to the Fc portion of human IgG1, in an in vitro model of human tuberculous granuloma. We showed that etanercept slightly delayed the formation of granuloma and reduced the generation of multinuclear giant cells (MGCs). In addition, etanercept exacerbated the expression of M1 polarization genes but also induced interleukin (IL)-10 release. In addition, our results indicated that etanercept inhibited cell fusion in an IL-10-dependent manner. Moreover, adalimumab, a human monoclonal anti-TNF-α IgG1 inhibited MGC formation in granuloma, without altering IL-10 secretion and induced macrophage apoptosis. Taken together, our data provides new insights into the role of TNF-α blockers in MGCs formation and the impact of such immunomodulatory drugs on tuberculous granuloma maturation.

The DosR antigen Rv1737c from Mycobacterium tuberculosis confers inflammation regulation in tuberculosis infection

There is an urgent need to identify the potential risk factors for activating latent Mycobacterium tuberculosis infection. In this study, we evaluated the immune function of Rv1737c, which is a latency-associated antigen of dormancy survival regulator (DosR) of M. tuberculosis in a mouse model. Our data showed that mice pretreated with recombinant Rv1737c (rRv1737c) exhibited higher levels of antigen-specific antibodies (IgG, IgM and IgA) than sham-treated mice. Following Bacilli Calmette-Guerin (BCG) challenge, rRv1737c adjuvanted with cholera toxin subunit B (CTB) induced diffuse lung inflammation and fibrosis compared to the control mice. The inflammatory pathogenesis due to rRv1737c pre-exposure was associated with a switch in the macrophage phenotype from M1 to activated M2 and was characterized by IL-10 production. Intracellular cytokine analysis further showed that the rRv1737c-pretreated mice exhibited an increased frequency of Th2 cells in the lungs, lymph nodes and spleen after BCG challenge. Furthermore, IFN-γ expression increased in the lungs after rRv1737c pretreatment compared to that in the sham mice. Accordingly, lung cells from rRv1737c-immunized mice stimulated with killed BCG produced higher levels of multiple cytokines, such as IFN-γ, IL-10 and IL-6. The results confirmed that the pathological features of rRv1737c promoted inflammation. Overall, our findings provide direct evidence of the pro-inflammatory function of rRv1737c in a murine model of BCG infection, indicating that Rv1737c is a pathogenic antigen of M. tuberculosis and may be key to the recurrence of latent infection.

Characterizing the Effects of Glutathione as an Immunoadjuvant in the Treatment of Tuberculosis

Mycobacterium tuberculosis is the etiological agent that is responsible for causing tuberculosis (TB), which continues to affect millions of people worldwide, and the rate of resistance of M. tuberculosis to antibiotics is ever increasing. We tested the synergistic effects of N-acetyl cysteine (NAC; the precursor molecule for the synthesis of glutathione [GSH]) and individual first-line antibiotics typically given for the treatment of TB, such as isoniazid (INH), rifampin (RIF), ethambutol (EMB), and pyrazinamide (PZA), to improve the ability of macrophages to control intracellular M. tuberculosis infection.

Mycobacterium tuberculosis is the etiological agent that is responsible for causing tuberculosis (TB), which continues to affect millions of people worldwide, and the rate of resistance of M. tuberculosis to antibiotics is ever increasing. We tested the synergistic effects of N-acetyl cysteine (NAC; the precursor molecule for the synthesis of glutathione [GSH]) and individual first-line antibiotics typically given for the treatment of TB, such as isoniazid (INH), rifampin (RIF), ethambutol (EMB), and pyrazinamide (PZA), to improve the ability of macrophages to control intracellular M. tuberculosis infection. GSH, a pleiotropic antioxidant molecule, has previously been shown to display both antimycobacterial and immune-enhancing effects. Our results indicate that there was not only an increase in beneficial immunomodulatory effects but also a greater reduction in the intracellular viability of M. tuberculosis when macrophages were treated with the combination of antibiotics (INH, RIF, EMB, or PZA) and NAC.

Interleukin-10 Family and Tuberculosis: An Old Story Renewed

The interleukin-10 (IL-10) family of cytokines consists of six immune mediators, namely IL-10, IL-19, IL-20, IL-22, IL-24 and IL-26. IL-10, IL-22, IL-24 and IL-26 are critical for the regulation of host defense against Mycobacterium tuberculosis infections. Specifically, IL-10 and IL-26 can suppress the antimycobacterial immunity and promote the survival of pathogen, while IL-22 and IL-24 can generate protective responses and inhibit the intracellular growth of pathogen. Knowledge about the new players in tuberculosis immunology, namely IL-10 family, can inform novel immunity-based countermeasures and host directed therapies against tuberculosis.

Diabetes Mellitus and Increased Tuberculosis Susceptibility: The Role of Short-Chain Fatty Acids

Type 2 diabetes mellitus confers a threefold increased risk for tuberculosis, but the underlying immunological mechanisms are still largely unknown. Possible mediators of this increased susceptibility are short-chain fatty acids, levels of which have been shown to be altered in individuals with diabetes. We examined the influence of physiological concentrations of butyrate on cytokine responses to Mycobacterium tuberculosis (Mtb) in human peripheral blood mononuclear cells (PBMCs). Butyrate decreased Mtb-induced proinflammatory cytokine responses, while it increased production of IL-10. This anti-inflammatory effect was independent of butyrate's well-characterised inhibition of HDAC activity and was not accompanied by changes in Toll-like receptor signalling pathways, the eicosanoid pathway, or cellular metabolism. In contrast blocking IL-10 activity reversed the effects of butyrate on Mtb-induced inflammation. Alteration of the gut microbiota, thereby increasing butyrate concentrations, can reduce insulin resistance and obesity, but further studies are needed to determine how this affects susceptibility to tuberculosis.

CARD15 Gene Polymorphisms Are Associated with Tuberculosis Susceptibility in Chinese Holstein Cows

Bovine tuberculosis (BTB) is a significant veterinary and financial problem in many parts of the world. Associations between specific host genes and susceptibility to mycobacterial infections, such as tuberculosis, have been reported in several species. The objective of this study was to identify and evaluate the relationship of single-nucleotide polymorphisms (SNPs) in the CARD15 gene with susceptibility to BTB in Chinese Holstein cows. DNA samples from 201 Chinese Holstein cows (103 cases and 98 controls) were collected from Kunming City, Yuxi City, and Dali City in China. SNPs in the CARD15 gene were assessed using polymerase chain reaction (PCR) and restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR). Case-control association testing and statistical analysis identified six SNPs associated with susceptibility to BTB in Chinese Holstein cows. The frequency of genotypes C/T, A/G, A/G, A/G, C/T, and A/G in E4 (-37), 208, 1644, 1648, 1799, and E10 (+107), respectively, was significantly higher in cases than in controls, and also the alleles C, A, A, G, T, and A, respectively, were associated with a greater relative risk in cases than in controls. The distribution of two haplotypes, TGGACA and CAGACA, was significantly different between cases and controls. Overall, this case-control study suggested that E4 (-37)(C/T), 208(A/G), 1644(A/G), 1648(A/G), 1799(C/T), and E10 (+107)(A/G) in the CARD15 gene were significantly associated with susceptibility to BTB in Chinese Holstein cows and that haplotypes TGGACA and CAGACA could be used as genetic markers in marker-assisted breeding programs for breeding cows with high resistance to BTB.

Characterization of host and microbial determinants in individuals with latent tuberculosis infection using a human granuloma model

Granulomas sit at the center of tuberculosis (TB) immunopathogenesis. Progress in biomarkers and treatment specific to the human granuloma environment is hindered by the lack of a relevant and tractable infection model that better accounts for the complexity of the host immune response as well as pathogen counterresponses that subvert host immunity in granulomas. Here we developed and characterized an in vitro granuloma model derived from human peripheral blood mononuclear cells (PBMCs) and autologous serum. Importantly, we interrogated this model for its ability to discriminate between host and bacterial determinants in individuals with and without latent TB infection (LTBI). By the use of this model, we provide the first evidence that granuloma formation, bacterial survival, lymphocyte proliferation, pro- and anti-inflammatory cytokines, and lipid body accumulation are significantly altered in LTBI individuals. Moreover, we show a specific transcriptional signature of Mycobacterium tuberculosis associated with survival within human granuloma structures depending on the host immune status. Our report provides fundamentally new information on how the human host immune status and bacterial transcriptional signature may dictate early granuloma formation and outcome and provides evidence for the validity of the granuloma model and its potential applications.

IMPORTANCE

In 2012, approximately 1.3 million people died from tuberculosis (TB), the highest rate for any single bacterial pathogen. The long-term control of TB requires a better understanding of Mycobacterium tuberculosis pathogenesis in appropriate research models. Granulomas represent the characteristic host tissue response to TB, controlling the bacilli while concentrating the immune response to a limited area. However, complete eradication of bacteria does not occur, since M. tuberculosis has its own strategies to adapt and persist. Thus, the M. tuberculosis-containing granuloma represents a unique environment for dictating both the host immune response and the bacterial response. Here we developed and characterized an in vitro granuloma model derived from blood cells of individuals with latent TB infection that more accurately defines the human immune response and metabolic profiles of M. tuberculosis within this uniquely regulated immune environment. This model may also prove beneficial for understanding other granulomatous diseases.

An unbiased genome-wide Mycobacterium tuberculosis gene expression approach to discover antigens targeted by human T cells expressed during pulmonary infection

Mycobacterium tuberculosis is responsible for almost 2 million deaths annually. Mycobacterium bovis bacillus Calmette-Guérin, the only vaccine available against tuberculosis (TB), induces highly variable protection against TB, and better TB vaccines are urgently needed. A prerequisite for candidate vaccine Ags is that they are immunogenic and expressed by M. tuberculosis during infection of the primary target organ, that is, the lungs of susceptible individuals. In search of new TB vaccine candidate Ags, we have used a genome-wide, unbiased Ag discovery approach to investigate the in vivo expression of 2170 M. tuberculosis genes during M. tuberculosis infection in the lungs of mice. Four genetically related but distinct mouse strains were studied, representing a spectrum of TB susceptibility controlled by the supersusceptibility to TB 1 locus. We used stringent selection approaches to select in vivo-expressed M. tuberculosis (IVE-TB) genes and analyzed their expression patterns in distinct disease phenotypes such as necrosis and granuloma formation. To study the vaccine potential of these proteins, we analyzed their immunogenicity. Several M. tuberculosis proteins were recognized by immune cells from tuberculin skin test-positive, ESAT6/CFP10-responsive individuals, indicating that these Ags are presented during natural M. tuberculosis infection. Furthermore, TB patients also showed responses toward IVE-TB Ags, albeit lower than tuberculin skin test-positive, ESAT6/CFP10-responsive individuals. Finally, IVE-TB Ags induced strong IFN-γ(+)/TNF-α(+) CD8(+) and TNF-α(+)/IL-2(+) CD154(+)/CD4(+) T cell responses in PBMC from long-term latently M. tuberculosis-infected individuals. In conclusion, these IVE-TB Ags are expressed during pulmonary infection in vivo, are immunogenic, induce strong T cell responses in long-term latently M. tuberculosis-infected individuals, and may therefore represent attractive Ags for new TB vaccines.